The subject matter of this application is related to that of co-pending application Ser. No. 618,163, filed on June 7, 1984.
The present invention relates to a numerical control device which can perform data communications with a variety of external computers.
A conventional numerical control device of this type is shown in FIG. 1. In FIG. 1, reference numeral 1 designates the numerical control device; 2, a paper tape on which numerical data has been recorded to cause the numerical control device 1 to issue instruction signals to a numerically controlled machine tool 4; and 3, an external computer for controlling the machine tool 4.
In this conventional device, numerical data is read from the tape 2 and applied through an input section 11 to a central processing unit (CPU) 12. The central processing unit 12 operates to cause an arithmetic section 13 to calculate control values for the machine tool 4, and thus the machine tool 4 is automatically controlled through an output section 15 according to conditions such as correction values for the machine tool set by a display section 14.
In order to perform such numerical control according to data from the external computer 3, a data transmitting and receiving section is provided in the central processing unit 12 to allow data communications between the central processing unit 12 and the external computer 3. In this conventional system, since the data communications method is determined in advance, it is necessary to employ the external computer 3, which is used only for the numerical control device 1, and to use exclusive data control character codes to perform data communications. In this connection, the data obtained by the control section 12 from the external computer 3 through the data transmitting and receiving section 12a is returned to the control section 12 after being converted into words by a transmitting and receiving data translating section 16a in a memory section 16 in the numerical control device 1.
In the conventional numerical control device constructed as described above, the external computer employable for data communications is limited: whenever a computer other than an exclusive computer is used as the external computer, a large number of data control character codes must be provided in the transmitting and receiving data transforming section. Thus, the conventional numerical control device is disadvantageous in that it is difficult for the device to use a microcomputer as its external computer.